login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A035891 Coordination sequence for diamond structure D^+_30. (Edges defined by l_1 norm = 1.) 0
1, 0, 1800, 0, 541200, 0, 65520920, 0, 4296107040, 0, 177923724072, 0, 5119703270960, 0, 109262828065080, 536870912, 1814093339150400, 249644974080, 24305082449321800, 21968757719040, 270526359458466384 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

REFERENCES

J. Serra-Sagrista, Enumeration of lattice points in l_1 norm, Information Processing Letters, 76, no. 1-2 (2000), 39-44.

LINKS

Table of n, a(n) for n=0..20.

J. H. Conway and N. J. A. Sloane, Low-Dimensional Lattices VII: Coordination Sequences, Proc. Royal Soc. London, A453 (1997), 2369-2389 (pdf).

MAPLE

f := proc(m) local k, t1; t1 := 2^(n-1)*binomial((n+2*m)/2-1, n-1); if m mod 2 = 0 then t1 := t1+add(2^k*binomial(n, k)*binomial(m-1, k-1), k=0..n); fi; t1; end; where n=30.

CROSSREFS

Sequence in context: A234203 A220058 A235898 * A069476 A179695 A025139

Adjacent sequences:  A035888 A035889 A035890 * A035892 A035893 A035894

KEYWORD

nonn

AUTHOR

Joan Serra-Sagrista (jserra(AT)ccd.uab.es)

EXTENSIONS

Recomputed by N. J. A. Sloane, Nov 27 1998

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 24 14:49 EDT 2019. Contains 323532 sequences. (Running on oeis4.)